Photographic developing apparatus



July 8, 1941. A. MILLER ETAL PHOTOGRAPHIC DEVELOPING APPARATUS Filed Dec. 31, 1938 Fig] Inventors Alfred Mil/er By The/I Afiwlplwrd Schmi f Patented July 8, 1941 PHOTOGRAPHIC DEVELOPING APPARATUS Alfred Miller and Gerhard Schmidt, Dessau, Germany, assignors, by mesne assignments, to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application December 31, 1938, Serial No. 248,773 In Germany January 3, 1938 4 Claims.

Our present invention relates to a photographic leveloping apparatus.

Various apparatus are known for developing m daylight light-sensitive photographic material, especially hand camera films and other amateur films, and treating them further up to the drying operation. Such apparatus consists in general of a container closed on all sides into which the film is introduced by a winding device in such a manner that during the treatment it is in constant motion. The commonest form is that in which there is a drum which can be rotated from without the vessel. The various treating liquids are admitted and withdrawn through suitably arranged inlets and outlets which may be such that light incident on them cannot pass into the developing box.

With the increasing applicability of amateur films, especially for color photography and re- .versal processes there has arisen a demand for a developing box which is suitable also for the socalled reversal development in which during the treatment, namely development or the like, an intermediate exposure of the photographic material is required. Moreover, especially in processes of developing color photographs it is necessary that the washing water should be changed more than once or, still better, allowed to fiow continuously through the apparatus.

It is an object of this invention to provide an improved apparatus for reversal development of film.

Further objects of the invention will be seen from the following description.

The principle of construction will be described with reference to the accompanying drawing to which, however, the actual construction is in no way limited.

In the drawing Figure 1 is a sectional view of a developing tank embodying one form of our invention,

Figure 2 is a similar view of such a tank showing a modified form of construction according to the invention, and

Figure 3 is a perspective view of a tank embodying a third modification of our basic inventive concept.

In each of Figures 1, 2 and 3, A represents a light-tight casing constructed of opaque material within which there is a spool C for winding up the film and capable of being rotated by means of the knob B. This spool and one of the sides of the casing are constructed of material highly transparent to light. In Fig. 1 the transparent side wall can be covered by a second wall or shutter D supported in grooves or the like so as to be capable of sliding or removal; by means of this wall or shutter the interior of the casing may be protected from penetration of undesired light.

In Fig. 2 the shutter D constitutes only a part of a second opaque wall of the casing.

In Fig. 3 the shutter is formed of sectors E. It will be understood that any other suitable mode of temporarily admitting actinic light to the easing may be adopted.

When the film spirally wound within the spool C has been developed and washed, the shutter or the like which has prevented access of light through the transparent wall may be wholly or partially withdrawn so that the contents of the casing are exposed to light. Uniformity of the exposure is favored by continuously turning the spool by means of the knob B. Moreover, the other walls of the casing may have reflecting internal surfaces so that a still greater uniformity of exposure over the whole spool may be obtained. When exposure to monochromatic light is required, a colored sheet may be inserted between the transparent wall of the casing and the shutter.

The treating liquids may be admitted and withdrawn in a manner usual for apparatus of this kind.

What we claim is:

1. An apparatus for reversal development of film comprising a receptacle, a film spool mounted therein for supporting the successive layers of said film in spaced relation to each other, and shutter means on said receptacle for selectively excluding and admitting actinic light with respect to the film on said spool within said receptacle at least a part of said spool transmitting the actinic light to said film to facilitate the second exposure of said film to such light.

2. An apparatus for reversal development of film comprising a receptacle, a film spool mounted therein for supporting the successive layers of said film in spaced relation to each other, and shutter means on said receptacle for selectively excluding and admitting actinic light with respect to the film on said spool within said receptacle, said spool being constructed at least in part of material transparent to actinic light to facilitate the second exposure of said film to such light.

3. An apparatus for reversal development of film comprising a receptacle, a film spool mounted therein for supporting the successive layers of said film in spaced relation to each other, and shutter means on said receptacle for selectively excluding and admitting actinic light with respect to the film on said spool within said receptacle, said spool and a side wall of said receptacle being constructed at least in part or material transparent to actinic light to facilitate the second exposure 01' said film to such light.

4. An apparatus for reversal development or film comprising a receptacle, a fllm spool mounted therein for supporting the successive layers of said film in spaced relation to each other, and i0 shutter means on said receptacle for selectively excluding and admitting actinic light with mpeet to the him on said spool within said receptacle. said spool and a side wall of said receptacle being constructed wholly or material transparent to actinic light to facilitate the second exposure of said film to such light.

ALFRED MILLER. GERHARD SCHMIDT. 

